Right click the small speaker icon most likely located lower right screen corner.
You will find a variety of options; e.g., Volume Mixer, Playback devices, Recording devices, etc.
Those selections lead to numerous windows, tabs, and properties that can be configured.
One such property is a function that caps or otherwise limits volume for sudden loud sounds. Handles music or other audio that is generally very low and may be hard to hear. You turn the volume up and then get your ears blasted when some instrument sounds off with some sudden emphatic notes.
It does appear that you have been working with those sort of configuration options. However, there may be some other control panel (audio related) or less obvious "check box" controlling the effect in question.
Then again you might just have some buggy drivers that do not immediately return your mic to normal voice after a loud sound - takes awhile to reset. The mic itself may be involved. Try some other mics if at all possible.
Could be a Teamspeak problem. Check their website, Forum, and FAQs.
Try updating your audio related drivers via the audio card manufacturer.